SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '838db89367f63db19f7256a31d9a09b097a8f8d42515943e912e8e8f93a7fa01' 
  AND token = '8JBTogjYAzVa6CSzSiYsvMKm0s9Zw+IIYW1r7xR32IQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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