SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31fcb9e41321defef310dcf53ef201e56965d3db46f257d39b90e9566bc53179' 
  AND token = 'FxH7D/TD0evjSvHDElb4bCmM/oryoVxOkhpBaC67src=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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