SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8b685bcc07e1547f6a491c36f3b11c146cf79809a4861a82226b384838802917' 
  AND token = 'VOfNuUzpcoY+GMnTI+F8Dc3wjbeuS5B9riXRx3EqaPE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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