SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7cb4dffd27bff089b9956a2c56a0b4fdf4837c3a7611e01d55f1e54dda81d351' 
  AND token = 'RFRzO7SI82MGIjhUGokRD/dex0Dd1xNsDG7qU1MUlyM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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