SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '269f4bc2c804e508808faeac4ef561212d5b8f1d93970da8981afb5944ce61b2' 
  AND token = 'sHXvJWVR9hAWZyBBSkFsr8Tad11tgmTdLTGHxMf6LTQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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