SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'dfa0d05024ce86a4b7a3314ee6ba52e99e192bb3cba69816a79bf2f29fd50dbe' 
  AND token = 's5Ba4Nbs8gDhZX1UKj3duAt5Ghl0mIqrGfp7KegVB0o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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