SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '33411dc2b547423104fe39f214791d64474c01467c2edaeb85c65782a8841193' 
  AND token = '2TegvR5BxIezxEOgFVjuPSIcb2BZXDkByCPUO1HjqHI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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