SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2223a61debf8959f82d17bd72d9763bfe1b6163305459a162e18ac07ea36c48' 
  AND token = 'Rn591+1QmPHPXIcMy82YQVbNWRlqvyiDOg9Hwqpm6+A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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