SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '453bfcb505f21677905c0dce4783451a9304e94846e0f989a7a1880b9e83c732' 
  AND token = '8yw9aJB4EnnuVEyionsRoFdR8x/ewv47xB3LlqdYlZs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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