SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b00883a1879a67da7916eb4e2700e8ef4d5055bc9cc425c12f7c632880e4f39' 
  AND token = 'voIrHin9R1QXgnFw8rjHdivJ+ihcK++UKwAgcxAu/Q0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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