SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4a167daaaffcefdc3e2fa80b8ff08bc2fa4a4f88f5ecf745791c7e5c52b488f' 
  AND token = 'QhlQSFP2bIfF0JUHpM9Ti+hntFErt4PWInqqMlWsSDI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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