SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ae9695893451542208a2978bcba342a963a6506dab2d10bfdaf150f825b858bd' 
  AND token = 'NEronviDWcieA+WKOJu5LlZBblb7sjqQrJIxWta/7gY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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