SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0c037f88cea475f72409e50a70fff3ee129a43e1b8aa74cbbc11b62bc203b25' 
  AND token = 'yoYIAotvYRx9RRq9l76lKWicAhqOFOfdE0UcLP1vKjE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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