SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '98cbb7e71d55b4642922c433dabdd0202739df82f7b2f6c0acf1df5040106c66' 
  AND token = '9/ponDshHjurGz9wywrqCV0OWJRCxFXowj/L/OFzjJk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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