SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a912fcb163c57463561f0b4ed902228e1c9c9ab52812a1f44abe193dabe449e3' 
  AND token = 'dGucmyA5opdVgsgL1QWBRLJlMj+uqp1l3a5sGn9upMY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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