SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b3657b49d14c844683f52eb0557622b0859ca92b3e5b95b8719de13b3b251216' 
  AND token = 'sUrMuVN+GImOGvriPKJGm85NECMtwLPFLm7QgPlkKyk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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