SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a60c5b6bf91ddbe2585401381fb15be8dca7d6945ba835460f3093ffc0c449a7' 
  AND token = 'Ukjzv0fkXvMnfdXqVuL4gFInJUdSz/68CxXJ/iSEbn4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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