SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '656874f52611865ea604a1eb3fef51da2749d64c6932913bdf233b45f88da640' 
  AND token = 'RWdhfIgv6vXspsLRI3AcDExsMwYwq1gGkPYkEnKRqVM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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