SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fee2c89d12274f87027a0edb499dce9cfeaca304975cbf9f0129121830b67913' 
  AND token = '+WjaIp0GdypFgdYIBj8R4OQ8t9YuJgF5uml8/mHR6UY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}