SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a3d2ded84a00ef638b0c835089d7ea045feb6a2809111dda21b6a0341516754' 
  AND token = 'jHAo8fI7UMvSai77jbJMm8OajSZZiG1p5viptTNesYg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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