SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e395f77645f01a8d52c5241979437ace33357c78336d36047f6ecc25575c9159' 
  AND token = 'S9u9DlyW2kbWjisk+iC+SyKXbRWUD2DL42ISWnQuK0Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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