SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '556c80672c1a67a3c74508310c35793e8a403049d2c4b2f9334a857a48b5981b' 
  AND token = 'NHVYKB0XwQ/zNp3KHLr+T1hves80dfdgqwbYEy/CuhE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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