SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6ee859379ceb4ffd3c0d69819907bfa0d13d5b44d8f7fe27b54d41a6cb79d59' 
  AND token = 'JPtcdmYN4yrAT7ByWm4IwcKfDbCnQ6vw8bXL6SKapuE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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