SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d5f356c0c2cb89a72a7fdc30eac7beff9074e3d00c1b1df2718d5184b250bff' 
  AND token = 'SwZBrs3R/LuWW0f1PoLD9NShrAPatJpuIabUOwYeThM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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