SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e67943ff5309f0cacc9a23f816b65586a8c6eb07c44b2dbfe4b711070de3192d' 
  AND token = 'mkV6l1TwywTHnuF4S7Uy5sHqpVH9kum0tAmrgt6dMow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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