SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '1f7ba25043883121184310b72f293c3514b6a1d931e771129346330b8626c904' 
  AND token = '73kaMUu9OXKgn0CghdZHFX9B+8ujWcYC626IpTHYAiw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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