SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45ca0a76d73d5f0a7602d1df471efd3ab66d57a411a0def901687a7b3f5a58c0' 
  AND token = '3w87q7x7jVwMEnacVopZCarLO10ibgTFgcm30+Zvjks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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