SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1d7d18805d9e2cce9bd521408c7ecd5c544516fc6cf268ea8339307158f6054' 
  AND token = '0zsA1bD9+tveuYgxmZZhwCiXp7GtWuthpIBbQbOQH9I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

JSON explain

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