SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7cbacbb376283c9a25648e7295caf655fbafdc4a3142c4853d1bb7a37f8549f1' 
  AND token = 'g5mxe8UuibVNHjf98TXKepHzlWBkNQbVrQYipjMY8Y0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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