SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a75cce169ffa0991903dbd09d5c577f9fd9c7aeb83b25aaed71caf46f784dd7' 
  AND token = 'sQHZW3R1rLaUKOqABX49QdajTovgwu1myW0vRvEyQec=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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