SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '01a2bbfc7c963a768fffb80053f74dc0cce365f855a4bea30e96b95039118199' 
  AND token = '8PoGYbVVxkrlfG7RIcCDHrh+om97AoXrrXPyQrnzkhs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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