SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37b7bea1e6a21899d94b1933a8d5f34e20e17c0da6d6386d42042276ab219407' 
  AND token = 'sgbevhlyWHmstanv7aHpoXWvuXvtelblduTHSsvdKOM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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