SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c6f6d5cc62dcc2b78981bbb57d278634d4942fe3f9ac73aa8036ca006384430' 
  AND token = 'JdW7dmBYkHOtfM1syckG9BEyuAGxj90cRmSML9BiqUk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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