SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91f76a250679c820d7941f37f9be53e617d5e1d6a0f43c0be82c2a41d713cfa6' 
  AND token = 'TFFaPlFhntcIWaQCg51HBlxOSgojkfH333QQz6EAS/c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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