SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2c4afee83c89728cdaa5685899cf0ca8ff4585e912341671c4b0e2346060bd8' 
  AND token = 'jZdggMMBSsTTs6JJHwElO1rTO3gcSgw2V2BITZBAoyc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00067

JSON explain

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