SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b81ac6b57c981648ab292d66ebf99f4e73aa2d7c3ab60168c667ebcaa9f93a38' 
  AND token = 'KV3b99mneIlZEdrTct6+mFnKU0/QK0uGPOGoHME9HNI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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