SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a445b1cc184343eb5bfbf2c846e9d5271b97564c588fd9a7f36d5eeab8bdcaf7' 
  AND token = 'riFDTjLF1KahJjdUvSfxpxP1LACEatTb5k2HfePVdfY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}