SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6686610422a3e8e3ef519e1fd42523fa098ca45473d9deaa0598e3600fc5a637' 
  AND token = 'Fokp9h6ZVSUXcMfshm2q6Ax5CDcGKfzEhzYg3vPpoi0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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