SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '599fcaf890d38eab2afebd5e42c9c4e2b982b2e8cd4e4696758525cc9d814542' 
  AND token = 'mX3GsGQGsYt07nEDOBCH/IARr0EVJ3/Lj2rG8vLkU6M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}