SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd114773cc9bd4b81f940c9f28a9c0313cd2b4c369acdaa91c89d0436caec0c5a' 
  AND token = 'leVqMjV6CCa+nrArNF5qPaKNVhJ8LgI/xtJCLmlOTDQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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