SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12ce64dd07a729ce16e42c78fbbd1d7c0428b6094fbdc70a8790730fc6db5600' 
  AND token = 'GQI86VhRzQLBNASfu+p/lrtN6DQVYSw2rq7CBmvTnKo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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