SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62ab0ed1e6c959986519343fd1dd98a290aa9662623b814cc97ba85d19e37005' 
  AND token = 'I/5lvK8kOxM+vDpgUHoBzWcischr7hJ3kMxpj0TXWtQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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