SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19151ab65c035300a3fe8191231e139596848a299a7c755aa088124e40bef9f2' 
  AND token = 'mHRFRS4xMr4f9NBiubGn8NVEOSOnusoYBFrvpgKVDAE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00079

JSON explain

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