SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3b63f27420680d14e5fd926fe830e9b55a83fba2a3ea255c302708683ab72f11' 
  AND token = 'JskwC7w40reM+r4o6h1GpltAiabJ+Sco9nA0pwXsCdo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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