SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '01c9e52535d3e55747ae7a8f1d77098e690bfc34943ba40c37962c9840af54f7' 
  AND token = 'KWTkm94raXLffzERX2bPhw+ZTqU+gSrzGVXujzw5ADI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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