SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1d7a984c1e9c12e4dfceec60a6f94d02e2ff1f877eefb74145be18d4eb492ac' 
  AND token = 'qT/gbpj7JGrGHdueGpZ1QoxB+uLWxnUoTDEKZOKeFWA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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