SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e53c3e59d2ebd540e29594a9d288e5ddbdf2fa3cc56ec4ab3958aa340767cf5c' 
  AND token = 'dN05iYHFyH0j9IYgwNEz9WhY+O05cO5haAEQohV+phI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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