SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5103b2b715e1e1dfe2cc82779d3cd77bfcab2a9811036a2a42565972dbba6bf9' 
  AND token = 'T4RN91JjgV8YGcjOkYdRAQJs3ouTmF2MYUgweTm9eEw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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