SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b77929db9e0ab4d2911b365796763592056a7fa8d184ce2ef1e8ec548ad318bc' 
  AND token = 'asypg35jHfVjw/8vhF/wFtZf3YmKK/BWvgJO0xu63dU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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