SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44b0104ccf43a45fe27f2eae921d94bd330d3588d417b87e9801becade24f7c9' 
  AND token = 'qSHsSDybRbhkuB8zxPWlQ89vClKQYmD6E9xcw312xN0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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