SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5918f1c98fd59ad275b76af92a87503339dc835979b001c0c4fcbd2f314ef66' 
  AND token = 'UUyjymGcfUBgzlU5AQgZzR7wLk1mZhTfnA0rnoVvSuU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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