SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b108c973ac27388f9c14a208e09e6a8c2d2f3a27cef857310c698f39220e775' 
  AND token = 'YrEZsuR+pnGXmcYvQ/+OLxwKMFhszV2pDrP3uHYLUrk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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