SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c39258f2af2915904d3a75b2fff4fb0de581d8bd294389124e41112b1f89f1bb' 
  AND token = 'PasQoDADzx+awoKrAjUqpTGdpBlJSwVQ7LqR+lB//08=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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