SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '126e0f4b911643ca742a4ab265886466059822617a12fe125d5ac25910fd3e60' 
  AND token = 'A6kJEm+m7zprwJXhx7+dVuY+1v/HvB1AU02xp6rjKQk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}