SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38853919a8e88054c987a2466ec2baffb5727daada29f813293d3fdf52e3614a' 
  AND token = 'h2+46oafBO2S9b/zPm9/AtcNtNojYZDtygJWmsHd0tY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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