SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4ebccfbb49e251d63902b7e285da3a230ebb93206e4df8d4f8967bacbbb7687' 
  AND token = 'oJ6qdOfgr8bxauMjoMy2UjT3vzLwwkwMokJRa0qIhSw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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