SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c93d596b4347859cca61db4954dcb70d3172dcf321fd41101f8afa58cf243ab' 
  AND token = 'W398G/WvYG947a0sMjqBlDJdrQk+yTA0KqSNW7wOo+k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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