SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'baf4c3cd6e526f13baec5c8587b6c8c32153614fa9962083789fd75017c90e3a' 
  AND token = 'ki2w3ILpREqtSbhkLsogCKHMwDSLwXrNAyeEwH7mEpQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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