SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '043a94d88a433bb33587a5b3e52876b368b3eef4b1cd08f6589baeac240f95b1' 
  AND token = 'lmv2ogvMJCQcCOMhfmzByy6LT7tfJ+ccj9bO5ctZurY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}