SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85538a4b5375383ae31f00b7a21de981957af415554ed45957844b9d47b474a3' 
  AND token = 'Ts7NNRyeSfyNjdK+z4J9cLF+v1+RauLnyUDhS2ZkXO0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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