SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef5242a7ffcc50096628efa73b743db16bd3f93477b0fb1ccbeee013273bd880' 
  AND token = 'YvM82lEnXtenbita9PvubWVoJHboHnIFqfFQ85YGV0A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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