SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '938637dfa0f90abe4011288715eaa254e199820dac5e8e702a23d250bf5b3ccd' 
  AND token = 'Nei1mzNwBTj9rFW3Y9DWAgMnvLe8ak73rowvYGYpjcI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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