SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7db6e94f16d288f8880c0bef9e6144946b89611c5e9eab322b53d7597961dfa9' 
  AND token = 'Z0za2F5F+f1kWrhtWuM6djThrCfv4cSe+FwXbNI/eeI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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