SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7dc240894b5a341e755ac1e35f578f322c25aeb277ac343e76327687687751ed' 
  AND token = 'KM8StwxRp6yMn8M0P7UWo5I5b8KAXB04NIcxcV9MeSc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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