SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2b71e8d628bdc7b54044b2483c5303515cd6a4e354bcf89869d82e40e094371' 
  AND token = 'ccoJHh6KxNDuyt1NWUIRMTKM27r61kRaIIl9OEFU+34=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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